CA2218432C - Module support structure - Google Patents
Module support structure Download PDFInfo
- Publication number
- CA2218432C CA2218432C CA002218432A CA2218432A CA2218432C CA 2218432 C CA2218432 C CA 2218432C CA 002218432 A CA002218432 A CA 002218432A CA 2218432 A CA2218432 A CA 2218432A CA 2218432 C CA2218432 C CA 2218432C
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- CA
- Canada
- Prior art keywords
- mounting
- module
- rails
- side walls
- bolt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- 230000007704 transition Effects 0.000 claims abstract description 19
- 230000000694 effects Effects 0.000 claims description 9
- 230000002427 irreversible effect Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000012546 transfer Methods 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002991 molded plastic Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
- H05K7/1422—Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames
- H05K7/1424—Card cages
- H05K7/1425—Card cages of standardised dimensions, e.g. 19"-subrack
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
- F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
- F16B35/06—Specially-shaped heads
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Mounting Of Printed Circuit Boards And The Like (AREA)
- Connection Of Plates (AREA)
- Mounting Components In General For Electric Apparatus (AREA)
- Casings For Electric Apparatus (AREA)
Abstract
A module support structure 1 is proposed for printed circuit boards 2 which can be inserted on guide rails 5.
The four parallel module rails 4 of the module support structure 1 to which the guide rails 5 are mounted are connected to the two parallel side walls 3 via a special mounting technique. Specially shaped mounting bolts 8 are used consisting essentially of a bolt head 11 having a flat seating surface 13, a substantially cylindrical threaded shaft 12, as well as a transition piece 19 disposed between the bolt head 11 and the threaded shaft 12 and tapering in a conical manner towards the threaded shaft 12. The mounting bolts 8 are fed through cylindrical mounting holes 9 in the side walls 3 and screwed into cylindrical holes 10 in the module rails 4. During tightening, the transition piece 19 abuts against the outer edge of the mounting holes 9 to force the module rails 4 against the projections 17 disposed above or below the mounting holes 9. In this manner, an exact positioning of the module rails 4 relative to the side walls 3 is necessarily effected. The outer edge of each mounting hole 9 can be deformed by the transition piece 19 until the seating surface 13 of the corresponding bolt head 11 seats on the side wall 3.
The four parallel module rails 4 of the module support structure 1 to which the guide rails 5 are mounted are connected to the two parallel side walls 3 via a special mounting technique. Specially shaped mounting bolts 8 are used consisting essentially of a bolt head 11 having a flat seating surface 13, a substantially cylindrical threaded shaft 12, as well as a transition piece 19 disposed between the bolt head 11 and the threaded shaft 12 and tapering in a conical manner towards the threaded shaft 12. The mounting bolts 8 are fed through cylindrical mounting holes 9 in the side walls 3 and screwed into cylindrical holes 10 in the module rails 4. During tightening, the transition piece 19 abuts against the outer edge of the mounting holes 9 to force the module rails 4 against the projections 17 disposed above or below the mounting holes 9. In this manner, an exact positioning of the module rails 4 relative to the side walls 3 is necessarily effected. The outer edge of each mounting hole 9 can be deformed by the transition piece 19 until the seating surface 13 of the corresponding bolt head 11 seats on the side wall 3.
Description
r Description The invention concerns a module support structure for printed circuit boards which can be inserted on guide rails, having two parallel side walls and at least four parallel module rails to which the guide rails can be mounted. The module rails comprise a cylindrical hole at each end for accepting a mounting bolt and the side walls have mounting holes for the mounting bolts and projections for positioning the module rails.
An exact guiding of the printed circuit board in the guide rails of a module support structure is clearly imperative, in particular for electronics applications in which multi-poled plugs of the smallest dimensions are used. The precise alignment of the guide rails depends, however, definitively on the precise, in particular vertical, positioning of the module rails on the side walls of the module support structure.
The side walls of conventional module support structures have inwardly directed projections, disposed at a particular separation above or below the mounting holes for the module rails. These projections function as positioning aids when mounting the module rails to the side walls. The module rails are positioned on the projections and the mounting bolts are then passed through the mounting holes of the side walls into the cylindrical holes of the module rails provided therefor.
For assembly or manufacturing purposes, the mounting holes in the side walls have an inner diameter which is significantly larger than the outer diameter of the mounting bolts. A displacement of the module rails perpendicular to the screw axis is therefore possible even when the mounting bolt seats in the mounting hole.
Problems thereby result, since the manual dexterity of the individual assembler determines whether or not the module rails actually seat on the corresponding projections after tightening the mounting bolts. Moreover, the module rails tend to rotate along with the mounting bolts when same are tightened.
As a result, in accordance with the described prior art, the close assembly tolerances necessary for the positioning of the guide rails for various applications can not be achieved or can only be achieved with an unacceptable degree of manual difficulty.
In order to achieve a restricted guidance seating of the module rails on the projections when tightening the mounting bolts, it has also been proposed that the mounting holes be countersunk in the outer side of the side walls and that beveled head bolts be used as mounting bolts.
However, this approach also has problems since, in this case as well, the inside diameter of the mounting holes is larger than the outer diameter of the threaded shaft of the mounting bolts. Consequently, the beveled head of a mounting bolt does not seat in the countersunk mounting hole at all sides, rather only at an upper section thereof, when the module rail is positioned on the projection. The frictional connection between the mounting bolts and the side wall is therefore unsatisfactory and causes concern that fatigue effects occur after longer periods of time. Moreover, the countersinking of the mounting holes in the side walls is very difficult from a manufacturing point of view.
It is therefore the underlying purpose of the invention to propose a module support structure comprising a new kind of bolt connection between the module support and the side components. The bolt connection should facilitate the maintenance of close installation tolerances in a simple fashion while neverthel~~~~s being capable of bearing high loads and being stable ~:wer a long period of time.
Therefore in accordance with the present invention there is provided a module su;~por~ structure for printed circuit boards which can be inserted on guide rails, having two parallel side walls and a.t: least four parallel module rails to which the guide rails can be mounted, wherein the module rails have a threaded cylindrical hole at each end for accepting a mounting bolt, and the side walls have cylindrical mounting holes for the mounting bolts and projections for positioning the module rails, characterized in that the mounting bolts consist essentially of a bolt head having a flat seating s~.zrface, an essentially cylindrical threaded shaft as well as a transition piece disposed between the bolt head and the t'.ireaded shaft and tapering in a conical manner towards r_h.E~ threaded shaft, wherein the -3a-threaded cylindrical holes in the module rails as well as the mounting holes and the projections on the side walls are each disposed in such a mannez~ that the transition piece, when tightening the mounting bolt, abuts against the outer edge of the mounting hole to thex-eby press the corresponding module rail against the associated projection, whereby tightening the mounting bolt effect: an irreversible deformation of the outer edge of the associat:ed mounting hole.
In accordance with the invention, a conventional module supporting structure of the above mentioned kind is therefore equipped with special mounting bolts consisting essentially of a bolt head haying a flat seating surface and an essentially cylindrical threaded shaft. A conical transition piece is disposed between the bolt head and the threaded shaft which tapers from the bolt head towards the threaded shaft. In addition, the dimensional configuration of the cylindrical holes in the ends of the module rails, of the mounting holes in the side walls, as well as of the projections is such that, when tightening the mounting bolts, their transition piece abuts against the outer edge of the mounting holes to direct the module rail against the projection via the thereby resulting reaction force.
The final frictional connection between a mounting bolt and the associated side wall results when the seating surface of the bolt head seats on the outer side of the side wall when the mounting bolt is tightened. The frictional connection therefore acts around all sides of the mounting hole. The invention thereby combines the advantages of a bolt connection via a cylindrical head bolt with those of a bolt connection via beveled head bolts, while avoiding the associated disadvantages of each. Moreover, a force component remains which permanently presses the module rail against the projection so that there is no danger that the module rail twists when the mounting bolt is tightened down.
Particular advantages result when the materials of the mounting bolts and the side walls are adapted to each other in such a manner that, when the mounting bolts are screwed-in, an irreversible deformation of the outer edge of the mounting hole begins to occur when the module rail seats on the associated projection and the transition piece integrated into the mounting bolt abuts against the outer edge of the mounting hole. Due to the abutting conical transition piece, the mounting bolt, and along with it, the module rail, is then moved towards the projection during tightening. This motion ends when the module rail seats on the projection. Further tightening of the mounting bolt causes deformation of the outer edge of the mounting hole so that the contact surface between the mounting bolt and the inside of the mounting hole is increased. A force component in the direction of the projection thereby acts on the module rail. When the seating surface of the bolt head finally seats on the outer side of the side wall, the screwing-in torque sharply increases to establish the frictional connection between the module rail and the side wall. The force transfer surface not only comprises the deformed inside of the mounting hole, rather moreover the contact surface, surrounding the mounting hole, between the side wall and the bolt head.
In order to effect electrical contact between the module rails and the side walls of the module support structure, it is advantageous when the mounting bolts have a plurality of contact spikes on the seating surface of their bolt heads which penetrate through the oxide layer of the side walls when the bolts are tightened. The contact spikes are preferentially triangular pyramids disposed in a barb-shaped fashion.
The effect in accordance with the invention of the specially shaped mounting bolts is preferentially achieved with a conical transition piece having a countersunk angle of about 60 angular degrees.
An exact guiding of the printed circuit board in the guide rails of a module support structure is clearly imperative, in particular for electronics applications in which multi-poled plugs of the smallest dimensions are used. The precise alignment of the guide rails depends, however, definitively on the precise, in particular vertical, positioning of the module rails on the side walls of the module support structure.
The side walls of conventional module support structures have inwardly directed projections, disposed at a particular separation above or below the mounting holes for the module rails. These projections function as positioning aids when mounting the module rails to the side walls. The module rails are positioned on the projections and the mounting bolts are then passed through the mounting holes of the side walls into the cylindrical holes of the module rails provided therefor.
For assembly or manufacturing purposes, the mounting holes in the side walls have an inner diameter which is significantly larger than the outer diameter of the mounting bolts. A displacement of the module rails perpendicular to the screw axis is therefore possible even when the mounting bolt seats in the mounting hole.
Problems thereby result, since the manual dexterity of the individual assembler determines whether or not the module rails actually seat on the corresponding projections after tightening the mounting bolts. Moreover, the module rails tend to rotate along with the mounting bolts when same are tightened.
As a result, in accordance with the described prior art, the close assembly tolerances necessary for the positioning of the guide rails for various applications can not be achieved or can only be achieved with an unacceptable degree of manual difficulty.
In order to achieve a restricted guidance seating of the module rails on the projections when tightening the mounting bolts, it has also been proposed that the mounting holes be countersunk in the outer side of the side walls and that beveled head bolts be used as mounting bolts.
However, this approach also has problems since, in this case as well, the inside diameter of the mounting holes is larger than the outer diameter of the threaded shaft of the mounting bolts. Consequently, the beveled head of a mounting bolt does not seat in the countersunk mounting hole at all sides, rather only at an upper section thereof, when the module rail is positioned on the projection. The frictional connection between the mounting bolts and the side wall is therefore unsatisfactory and causes concern that fatigue effects occur after longer periods of time. Moreover, the countersinking of the mounting holes in the side walls is very difficult from a manufacturing point of view.
It is therefore the underlying purpose of the invention to propose a module support structure comprising a new kind of bolt connection between the module support and the side components. The bolt connection should facilitate the maintenance of close installation tolerances in a simple fashion while neverthel~~~~s being capable of bearing high loads and being stable ~:wer a long period of time.
Therefore in accordance with the present invention there is provided a module su;~por~ structure for printed circuit boards which can be inserted on guide rails, having two parallel side walls and a.t: least four parallel module rails to which the guide rails can be mounted, wherein the module rails have a threaded cylindrical hole at each end for accepting a mounting bolt, and the side walls have cylindrical mounting holes for the mounting bolts and projections for positioning the module rails, characterized in that the mounting bolts consist essentially of a bolt head having a flat seating s~.zrface, an essentially cylindrical threaded shaft as well as a transition piece disposed between the bolt head and the t'.ireaded shaft and tapering in a conical manner towards r_h.E~ threaded shaft, wherein the -3a-threaded cylindrical holes in the module rails as well as the mounting holes and the projections on the side walls are each disposed in such a mannez~ that the transition piece, when tightening the mounting bolt, abuts against the outer edge of the mounting hole to thex-eby press the corresponding module rail against the associated projection, whereby tightening the mounting bolt effect: an irreversible deformation of the outer edge of the associat:ed mounting hole.
In accordance with the invention, a conventional module supporting structure of the above mentioned kind is therefore equipped with special mounting bolts consisting essentially of a bolt head haying a flat seating surface and an essentially cylindrical threaded shaft. A conical transition piece is disposed between the bolt head and the threaded shaft which tapers from the bolt head towards the threaded shaft. In addition, the dimensional configuration of the cylindrical holes in the ends of the module rails, of the mounting holes in the side walls, as well as of the projections is such that, when tightening the mounting bolts, their transition piece abuts against the outer edge of the mounting holes to direct the module rail against the projection via the thereby resulting reaction force.
The final frictional connection between a mounting bolt and the associated side wall results when the seating surface of the bolt head seats on the outer side of the side wall when the mounting bolt is tightened. The frictional connection therefore acts around all sides of the mounting hole. The invention thereby combines the advantages of a bolt connection via a cylindrical head bolt with those of a bolt connection via beveled head bolts, while avoiding the associated disadvantages of each. Moreover, a force component remains which permanently presses the module rail against the projection so that there is no danger that the module rail twists when the mounting bolt is tightened down.
Particular advantages result when the materials of the mounting bolts and the side walls are adapted to each other in such a manner that, when the mounting bolts are screwed-in, an irreversible deformation of the outer edge of the mounting hole begins to occur when the module rail seats on the associated projection and the transition piece integrated into the mounting bolt abuts against the outer edge of the mounting hole. Due to the abutting conical transition piece, the mounting bolt, and along with it, the module rail, is then moved towards the projection during tightening. This motion ends when the module rail seats on the projection. Further tightening of the mounting bolt causes deformation of the outer edge of the mounting hole so that the contact surface between the mounting bolt and the inside of the mounting hole is increased. A force component in the direction of the projection thereby acts on the module rail. When the seating surface of the bolt head finally seats on the outer side of the side wall, the screwing-in torque sharply increases to establish the frictional connection between the module rail and the side wall. The force transfer surface not only comprises the deformed inside of the mounting hole, rather moreover the contact surface, surrounding the mounting hole, between the side wall and the bolt head.
In order to effect electrical contact between the module rails and the side walls of the module support structure, it is advantageous when the mounting bolts have a plurality of contact spikes on the seating surface of their bolt heads which penetrate through the oxide layer of the side walls when the bolts are tightened. The contact spikes are preferentially triangular pyramids disposed in a barb-shaped fashion.
The effect in accordance with the invention of the specially shaped mounting bolts is preferentially achieved with a conical transition piece having a countersunk angle of about 60 angular degrees.
An embodiment of the invention is more closely described below with reference to the associated drawings.
Figure 1 shows a schematic perspective representation of a module support structure;
Figure 2a schematically shows the mounting of a module rail to a side wall according to prior art;
Figure 2b schematically shows the mounting of a module rail to a side wall according to a different prior art;
Figure 2c schematically shows the mounting of the module rail in accordance with the invention to a side wall;
Figure 3 shows a mounting bolt formed in accordance with the invention;
Figure 4 shows a view in direction A of figure 3.
The module support structure 1 shown in figure 1 is intended to accept a large number of printed circuit boards 2, which are adapted for insertion and equipped with electrical and electronic components (not shown). The module support structure 1 consists essentially of two rectangular, parallel side walls 3 and four parallel module rails 4.
The four module rails 4, made from extruded aluminum, connect the two side walls 3. The two lower module rails 4 as well as the two upper module rails 4 each support an upper and lower guide rail 5, respectively. These guide rails 5 are mounted transverse to the module rails 4 using resilient clamping elements. The clamping elements snap into slotted holes 6 for equidistant disposition of the module rails 4. The guide rails 5 are made from molded plastic and each have a guide groove 7 for accepting the printed circuit boards 2.
The module rails 4 are mounted to the side walls 3 using mounting bolts 8. The mounting bolts 8 pass through associated mounting holes 9 in the side walls 3 and are screwed into cylindrical holes 10 in the module rails 4.
Figure 2 shows, in detail, the connection between the module rails 4 and the side walls 3 using the mounting -bolts 8. Figures 2a and 2b are taken from prior art and figure 2c shows the mounting technique in accordance with the invention.
Figure 2a illustrates common prior art, wherein a mounting bolt 8, having a cylindrical bolt head 11, is screwed through a mounting hole 9 in the side wall 3 into a cylindrical hole 10 in the module rail 4. The cylindrical threaded shaft 12 of the mounting bolt 8 extends in a cylindrical manner up to the bolt head 11 seating surface 13. The outer diameter of the threaded shaft 12 is, for assembly or manufacturing reasons, smaller than the inner diameter of the mounting hole 9, so that the actual axis 14 of the mounting bolt 8 can be displaced, in particular in the directions indicated by the arrow having reference number 15. The lower edge 16 of the module rail 4 must _g_ seat on the projection 17 provided therefor to effect an exact positioning of the module rail 4 on the side wall 3, particularly in the vertical direction. The person assembling the module support structure 1 must therefore take care, when tightening down the mounting bolt 8, that the actual axis 14 ccincides with the desired axis 18. At the same time, the module rails 4 must not be rotated by the torque applied to the mounting bolt 8.
Figure 2b shows a configuration for mounting a module rail 4 to a side wall 3 which is sometimes used in prior art.
In this case, the mounting bolt 8 is a beveled head bolt having a cylindrical threaded shaft 12 which is screwed through a mounting hole 9 in the side wall 3 into a cylindrical hole 10 in the module rail 4. The mounting hole 9 must be countersunk for acceptance of the bolt head 11 of the mounting bolt 8. In this case as well, the lower edge 16 of the module rail 4 must seat on the projection 17 of the side wall 3 to guarantee an exact alignment of the module rail 4. However, in accordance with the prior art as shown here, the screwing-in of the mounting bolt 8 causes, through the cooperation between the bolt head 11 and the countersink of the mounting hole 9, a forced . guiding of the module rail 4 in the direction of arrow 15 until it seats on projection 17. Therefore the installer must not take particular care that the actual axis 14 and the desired axis 18 coincide.
However, as clearly shown in figure 2b, the use of a beveled head screw in conjunction with the countersunk mounting holes 9 causes the force transfer surface between the module rail 4 and the side wall 3 to be limited to the _g_ upper portion of the seating surface 13 of the bolt head 11. In most cases, the seating surface 13 only contacts the countersunk mounting hole 9 within a small angular re~ion of its periphery. This significantly reduces the stability and load capability of the connection shown.
Figure 2c shows the connection between a module rail 4 and a side wall 3 in accordance with the invention using a specially formed mounting bolt 8. The mounting bolt 8 consists essentially of a cylindrical bolt head 11 and an adjacent transition piece 19 which tapers in a conical manner towards the cylindrical threaded shaft 12. The mounting hole 9 in the side wall 3 is cylindrical in shape. Its inner diameter is larger than the outer diameter of the threaded shaft 12.
The mounting bolt 8 is initially screwed, without substantial resistance, into the cylindrical hole 10 of the module rail 4 along the actual axis 14. As soon as the transition piece 19 abuts with the inner edge of the mounting hole 9, a forced movement of the module rail 4 in the direction of arrow 15 results. When the lower edge 16 of the module rail 4 seats on the projection 17, and the actual axis 14 coincides with the desired axis 18, the screw-in torque of the mounting bolt 8 increases sharply.
However at this time, the seating surface 13 of the bolt head 11 does not yet seat on the outer side of the side wall 3: the mounting bolt 8 can be tightened somewhat further. This tightening motion causes the inner edge of the mounting hole 9 to deform irreversibly in deformation region 20, to increase the connection surface between the inside of the mounting hole 9 and the outer side of the transition piece 19. This process continues until the seating surface 13 of the bolt head 11 seats at all sides on the region of the side wall 3 surrounding the mounting hole 9 to effect the permanent~frictional connection between the module rail 4 and the side wall 3. Even after the mounting bolt 8 is completely tightened, a force component remains which acts on the module rail 4 in the direction of arrow 15 so that the exact alignment of the module rail 4 is guaranteed even when strongly loaded, e.g. with a heavy inserted printed circuit board 2 and/or in the event of vibrations and shaking.
Figure 3 shows, to scale, a mounting bolt 8 configured in accordance with the invention. The half-round basically cylindrically-shaped bolt head 11 is connected to the cylindrical threaded shaft 12 via the conical transition piece 19. The seating surface 13 of the bolt head 11 supports contact spikes 21 disposed in a barbed-shaped manner to guarantee contact between the mounting bolt 8 and a side wall 3, even through an oxide layer.
Figure 4 shows the mounting bolt 8 of figure 3 in a view from direction A. In addition to the threaded shaft 12, the transition piece 19, and the seating surface 13 of the bolt head 11, one clearly sees that a total of four contact spikes 21 are disposed on the seating surface 13 at mutually spaced angles of 90 degrees. The barbed-shape of the contact spikes 21 has the advantageous side effect that the mounting bolts 8 do not loosen as easily under vibration and shaking.
Summary of Reference Symbols 1 module support structure 2 printed circuit board 3 side walls 4 module rails guide rails 6 slotted hole 7 guide groove 8 mounting bolts 9 mounting holes (in 3) holes (in 4) 11 bolt head 12 threaded shaft 13 seating surface (of 11) 14 actual axis (of 8) arrow 16 lower edge (of 4) 17 projections 18 desired axis (of 8) 19 transition piece (of 8) deformation region (of 3) 21 contact spikes
Figure 1 shows a schematic perspective representation of a module support structure;
Figure 2a schematically shows the mounting of a module rail to a side wall according to prior art;
Figure 2b schematically shows the mounting of a module rail to a side wall according to a different prior art;
Figure 2c schematically shows the mounting of the module rail in accordance with the invention to a side wall;
Figure 3 shows a mounting bolt formed in accordance with the invention;
Figure 4 shows a view in direction A of figure 3.
The module support structure 1 shown in figure 1 is intended to accept a large number of printed circuit boards 2, which are adapted for insertion and equipped with electrical and electronic components (not shown). The module support structure 1 consists essentially of two rectangular, parallel side walls 3 and four parallel module rails 4.
The four module rails 4, made from extruded aluminum, connect the two side walls 3. The two lower module rails 4 as well as the two upper module rails 4 each support an upper and lower guide rail 5, respectively. These guide rails 5 are mounted transverse to the module rails 4 using resilient clamping elements. The clamping elements snap into slotted holes 6 for equidistant disposition of the module rails 4. The guide rails 5 are made from molded plastic and each have a guide groove 7 for accepting the printed circuit boards 2.
The module rails 4 are mounted to the side walls 3 using mounting bolts 8. The mounting bolts 8 pass through associated mounting holes 9 in the side walls 3 and are screwed into cylindrical holes 10 in the module rails 4.
Figure 2 shows, in detail, the connection between the module rails 4 and the side walls 3 using the mounting -bolts 8. Figures 2a and 2b are taken from prior art and figure 2c shows the mounting technique in accordance with the invention.
Figure 2a illustrates common prior art, wherein a mounting bolt 8, having a cylindrical bolt head 11, is screwed through a mounting hole 9 in the side wall 3 into a cylindrical hole 10 in the module rail 4. The cylindrical threaded shaft 12 of the mounting bolt 8 extends in a cylindrical manner up to the bolt head 11 seating surface 13. The outer diameter of the threaded shaft 12 is, for assembly or manufacturing reasons, smaller than the inner diameter of the mounting hole 9, so that the actual axis 14 of the mounting bolt 8 can be displaced, in particular in the directions indicated by the arrow having reference number 15. The lower edge 16 of the module rail 4 must _g_ seat on the projection 17 provided therefor to effect an exact positioning of the module rail 4 on the side wall 3, particularly in the vertical direction. The person assembling the module support structure 1 must therefore take care, when tightening down the mounting bolt 8, that the actual axis 14 ccincides with the desired axis 18. At the same time, the module rails 4 must not be rotated by the torque applied to the mounting bolt 8.
Figure 2b shows a configuration for mounting a module rail 4 to a side wall 3 which is sometimes used in prior art.
In this case, the mounting bolt 8 is a beveled head bolt having a cylindrical threaded shaft 12 which is screwed through a mounting hole 9 in the side wall 3 into a cylindrical hole 10 in the module rail 4. The mounting hole 9 must be countersunk for acceptance of the bolt head 11 of the mounting bolt 8. In this case as well, the lower edge 16 of the module rail 4 must seat on the projection 17 of the side wall 3 to guarantee an exact alignment of the module rail 4. However, in accordance with the prior art as shown here, the screwing-in of the mounting bolt 8 causes, through the cooperation between the bolt head 11 and the countersink of the mounting hole 9, a forced . guiding of the module rail 4 in the direction of arrow 15 until it seats on projection 17. Therefore the installer must not take particular care that the actual axis 14 and the desired axis 18 coincide.
However, as clearly shown in figure 2b, the use of a beveled head screw in conjunction with the countersunk mounting holes 9 causes the force transfer surface between the module rail 4 and the side wall 3 to be limited to the _g_ upper portion of the seating surface 13 of the bolt head 11. In most cases, the seating surface 13 only contacts the countersunk mounting hole 9 within a small angular re~ion of its periphery. This significantly reduces the stability and load capability of the connection shown.
Figure 2c shows the connection between a module rail 4 and a side wall 3 in accordance with the invention using a specially formed mounting bolt 8. The mounting bolt 8 consists essentially of a cylindrical bolt head 11 and an adjacent transition piece 19 which tapers in a conical manner towards the cylindrical threaded shaft 12. The mounting hole 9 in the side wall 3 is cylindrical in shape. Its inner diameter is larger than the outer diameter of the threaded shaft 12.
The mounting bolt 8 is initially screwed, without substantial resistance, into the cylindrical hole 10 of the module rail 4 along the actual axis 14. As soon as the transition piece 19 abuts with the inner edge of the mounting hole 9, a forced movement of the module rail 4 in the direction of arrow 15 results. When the lower edge 16 of the module rail 4 seats on the projection 17, and the actual axis 14 coincides with the desired axis 18, the screw-in torque of the mounting bolt 8 increases sharply.
However at this time, the seating surface 13 of the bolt head 11 does not yet seat on the outer side of the side wall 3: the mounting bolt 8 can be tightened somewhat further. This tightening motion causes the inner edge of the mounting hole 9 to deform irreversibly in deformation region 20, to increase the connection surface between the inside of the mounting hole 9 and the outer side of the transition piece 19. This process continues until the seating surface 13 of the bolt head 11 seats at all sides on the region of the side wall 3 surrounding the mounting hole 9 to effect the permanent~frictional connection between the module rail 4 and the side wall 3. Even after the mounting bolt 8 is completely tightened, a force component remains which acts on the module rail 4 in the direction of arrow 15 so that the exact alignment of the module rail 4 is guaranteed even when strongly loaded, e.g. with a heavy inserted printed circuit board 2 and/or in the event of vibrations and shaking.
Figure 3 shows, to scale, a mounting bolt 8 configured in accordance with the invention. The half-round basically cylindrically-shaped bolt head 11 is connected to the cylindrical threaded shaft 12 via the conical transition piece 19. The seating surface 13 of the bolt head 11 supports contact spikes 21 disposed in a barbed-shaped manner to guarantee contact between the mounting bolt 8 and a side wall 3, even through an oxide layer.
Figure 4 shows the mounting bolt 8 of figure 3 in a view from direction A. In addition to the threaded shaft 12, the transition piece 19, and the seating surface 13 of the bolt head 11, one clearly sees that a total of four contact spikes 21 are disposed on the seating surface 13 at mutually spaced angles of 90 degrees. The barbed-shape of the contact spikes 21 has the advantageous side effect that the mounting bolts 8 do not loosen as easily under vibration and shaking.
Summary of Reference Symbols 1 module support structure 2 printed circuit board 3 side walls 4 module rails guide rails 6 slotted hole 7 guide groove 8 mounting bolts 9 mounting holes (in 3) holes (in 4) 11 bolt head 12 threaded shaft 13 seating surface (of 11) 14 actual axis (of 8) arrow 16 lower edge (of 4) 17 projections 18 desired axis (of 8) 19 transition piece (of 8) deformation region (of 3) 21 contact spikes
Claims (4)
1. A module support structure for printed circuit boards which can be inserted on guide rails, having two parallel side walls and at least four parallel module rails to which the guide rails can be mounted, wherein the module rails have a threaded cylindrical hole at each end for accepting a mounting bolt, and the side walls have cylindrical mounting holes for the mounting bolts and projections for positioning the module rails, characterized in that the mounting bolts consist essentially of a bolt head having a flat seating surface, an essentially cylindrical threaded shaft as well as a transition piece disposed between the bolt head and the threaded shaft and tapering in a conical manner towards the threaded shaft, wherein the threaded cylindrical holes in the module rails as well as tree mounting holes and the projections on the side walls are each disposed in such a manner that the transition piece, when tightening the mounting bolt, abuts against the outer edge of the mounting hole to thereby press the corresponding module rail against the associated projection, whereby tightening the mounting bolt effects an irreversible deformation of the outer edge of the associated mounting hole.
2. The module support structure of claim 1, characterized in that the seating surfaces of the bolt head each have a plurality of contact spikes to effect contact between the mounting bolts and the side walls.
3. The module support structure of claim 2, characterized in that the contact spikes are triangular pyramids disposed in a barb-shaped fashion.
4. The module support structure of any one of the claims 1 through 3, characterized in that the transition pieces of the mounting bolts have a beveled angle of about 60 angular degrees.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19644419A DE19644419C1 (en) | 1996-10-25 | 1996-10-25 | Component group carrier for circuit boards inserted on guide rails |
| DE19644419.5 | 1996-10-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2218432A1 CA2218432A1 (en) | 1998-04-25 |
| CA2218432C true CA2218432C (en) | 2001-09-25 |
Family
ID=7809996
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002218432A Expired - Fee Related CA2218432C (en) | 1996-10-25 | 1997-10-16 | Module support structure |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US6065614A (en) |
| EP (1) | EP0838984B1 (en) |
| JP (1) | JP2903011B2 (en) |
| KR (1) | KR100287028B1 (en) |
| AU (1) | AU701713B2 (en) |
| CA (1) | CA2218432C (en) |
| CZ (1) | CZ285934B6 (en) |
| DE (1) | DE19644419C1 (en) |
| ID (1) | ID18688A (en) |
| MY (1) | MY117866A (en) |
| PL (1) | PL183734B1 (en) |
| SG (1) | SG53106A1 (en) |
| TW (1) | TW444525B (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19644418C5 (en) * | 1996-10-25 | 2004-10-28 | Schroff Gmbh | rack |
| DE19817089C1 (en) * | 1998-04-17 | 1999-08-19 | Schroff Gmbh | Carrier for accommodating plug-in assemblies fitted with electrical and electronic components |
| GB2372304B (en) * | 2001-02-14 | 2004-09-08 | Jeffrey Slee | Gripping points for bolt mating surfaces applicable to any stud/bolt/head/washer/nut assembly |
| DE10230589B4 (en) * | 2002-07-05 | 2012-05-10 | C. Rob. Hammerstein Gmbh & Co. Kg | Play-free joint for motor vehicle seats |
| DE10245120B3 (en) * | 2002-09-27 | 2004-03-04 | Siemens Ag | Component module rack for electrical and/or electronic apparatus, has projecting edges of guide rails provided with openings and holes for cooperating with component module contact and coupling device |
| US10085780B2 (en) | 2006-05-26 | 2018-10-02 | Mark Richard Cunliffe | Bone fixation device |
| US20120029576A1 (en) * | 2006-05-26 | 2012-02-02 | Mark Richard Cunliffe | Bone Fixation Device |
| EP2019210A1 (en) * | 2007-07-25 | 2009-01-28 | Lisi Automotive Rapid | Fixing device consisting of a plastic screw and a nut |
| JP5804819B2 (en) * | 2010-08-04 | 2015-11-04 | キヤノン株式会社 | Structure and image forming apparatus |
| CN103687412A (en) * | 2012-08-31 | 2014-03-26 | 技嘉科技股份有限公司 | Server Cabinet |
| US10201110B1 (en) * | 2014-02-19 | 2019-02-05 | Lockheed Martin Corporation | Device rack incorporating multiple mounting planes |
| CN105673657B (en) * | 2016-03-23 | 2017-07-28 | 南京林业大学 | Pre-tightening and anti-loosening mechanism of piezoelectric sensor |
| US10495237B1 (en) | 2017-03-29 | 2019-12-03 | Robroy Industries—Texas, LLC | Piping and conduit support rack |
| DE202017004671U1 (en) * | 2017-09-07 | 2018-12-10 | Dieter Ramsauer | Grounding screw with segmental cutting edge |
| US20190242425A1 (en) * | 2018-02-02 | 2019-08-08 | Dell Products L.P. | Screw with anti-loosening features |
| CN110381683A (en) * | 2019-07-09 | 2019-10-25 | Oppo（重庆）智能科技有限公司 | Earthing member, shell and electronic device |
| DE102021100601B4 (en) * | 2020-10-16 | 2022-10-06 | Adient Us Llc | FOREIGN ADJUSTER, METHOD OF INSTALLATION OF A FOREIGN ADJUSTER AND VEHICLE SEAT |
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| US1821709A (en) * | 1930-07-28 | 1931-09-01 | Western Railway Equipment Comp | Bolt |
| US3145362A (en) * | 1961-01-04 | 1964-08-18 | Rosemount Eng Co Ltd | Electrical resistance device |
| DE1947550U (en) * | 1966-03-03 | 1966-10-13 | Standard Elektrik Lorenz Ag | FASTENING OF PROFILE RAILS ON SIDE PANELS. |
| US3465891A (en) * | 1967-06-23 | 1969-09-09 | Itt | Printed circuit board library rack |
| DE2653468C2 (en) * | 1976-11-25 | 1982-02-25 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Subrack |
| US4228723A (en) * | 1977-09-16 | 1980-10-21 | Cunningham Hilary H | Fastener recess |
| EP0038652A3 (en) * | 1980-04-21 | 1982-07-14 | Vero Electronics Limited | Electrical bonding of metal components |
| US4462730A (en) * | 1981-02-02 | 1984-07-31 | Illinois Tool Works Inc. | Painted screw and washer assemblies |
| DE3133638A1 (en) * | 1981-08-26 | 1983-03-10 | Richard Bergner GmbH & Co, 8540 Schwabach | Screw having a toothed head contact surface |
| DE3241066A1 (en) * | 1982-11-06 | 1984-05-10 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Mounting rack for electrical and electronic assemblies |
| DE3241067A1 (en) * | 1982-11-06 | 1984-05-10 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Mounting rack for electronic assemblies |
| US4764066A (en) * | 1985-04-22 | 1988-08-16 | Farley Metals, Inc. | Light gauge self-tapping sheet metal screw |
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-
1996
- 1996-10-25 DE DE19644419A patent/DE19644419C1/en not_active Expired - Lifetime
-
1997
- 1997-09-30 EP EP97116933A patent/EP0838984B1/en not_active Expired - Lifetime
- 1997-10-16 CA CA002218432A patent/CA2218432C/en not_active Expired - Fee Related
- 1997-10-16 SG SG1997003764A patent/SG53106A1/en unknown
- 1997-10-23 ID IDP973505A patent/ID18688A/en unknown
- 1997-10-23 JP JP9290788A patent/JP2903011B2/en not_active Expired - Fee Related
- 1997-10-23 PL PL97322799A patent/PL183734B1/en not_active IP Right Cessation
- 1997-10-24 US US08/957,451 patent/US6065614A/en not_active Expired - Fee Related
- 1997-10-24 AU AU42847/97A patent/AU701713B2/en not_active Ceased
- 1997-10-24 TW TW086115765A patent/TW444525B/en active
- 1997-10-24 MY MYPI97005024A patent/MY117866A/en unknown
- 1997-10-24 KR KR1019970054571A patent/KR100287028B1/en not_active IP Right Cessation
- 1997-10-27 CZ CZ973415A patent/CZ285934B6/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| PL183734B1 (en) | 2002-07-31 |
| EP0838984A3 (en) | 1998-06-24 |
| US6065614A (en) | 2000-05-23 |
| SG53106A1 (en) | 1998-09-28 |
| CZ341597A3 (en) | 1998-05-13 |
| AU4284797A (en) | 1998-05-21 |
| AU701713B2 (en) | 1999-02-04 |
| MY117866A (en) | 2004-08-30 |
| CZ285934B6 (en) | 1999-11-17 |
| KR100287028B1 (en) | 2001-04-16 |
| KR19980033114A (en) | 1998-07-25 |
| TW444525B (en) | 2001-07-01 |
| PL322799A1 (en) | 1998-04-27 |
| EP0838984A2 (en) | 1998-04-29 |
| JPH10135667A (en) | 1998-05-22 |
| CA2218432A1 (en) | 1998-04-25 |
| DE19644419C1 (en) | 1997-11-27 |
| JP2903011B2 (en) | 1999-06-07 |
| ID18688A (en) | 1998-04-30 |
| EP0838984B1 (en) | 2003-02-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |